Dual-mode organic photodiode based on barrier layer interface regulation and preparation method

Abstract

The present invention provides a dual-mode organic photodiode based on barrier layer interface regulation and a preparation method, comprising a transparent substrate layer and a five-layer material structure, wherein the five-layer material structure comprises a transparent bottom electrode layer, a first barrier layer, an organic photosensitive layer, a second barrier layer, and a top electrode layer; under forward bias, carrier traps at the interface between the barrier layer and the photosensitive layer trigger tunneling injection of carriers from the external circuit, and the device operates in PM mode with high external quantum efficiency, which is suitable for weak light detection and can avoid the use of a preamplifier circuit. Under reverse bias, the barrier layers on both sides of the photosensitive layer can prevent the injection of carriers from the external circuit, and the device operates in PV mode with limited external quantum efficiency, which is suitable for strong light detection and can avoid problems such as device heat dissipation and breakdown caused by high power consumption. The present invention proposes a method for preparing a dual-mode device by regulating the barrier layer interface, which optimizes the optoelectronic performance of the dual-mode device, thereby providing a solution for the preparation of dual-mode organic photodiodes.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic semiconductors, and in particular relates to a dual-mode organic photodiode based on barrier layer interface regulation, which is suitable for light detection under both strong and weak conditions. Background Art

[0002] In today's information-based society, there is an increasing demand for highly integrated microelectronic devices that are increasingly smaller, more affordable, and offer more functionality. Photodiodes, with their advantages of small size, ease of integration, low dark current, and fast response, are widely used in imaging systems such as CCD / CMOS arrays. In recent years, organic photodiodes have attracted considerable attention due to their compatibility with flexible substrates, wide range of material modification options, tunable response spectra, lightweight design, and amenability to large-scale fabrication.

[0003] Due to the rectification characteristics of photodiodes, the dark current of general photodiode devices under forward bias is very high and the stability of light and dark current under constant voltage cannot be guaranteed. Therefore, devices under forward bias cannot be used for light signal detection. Therefore, photodiodes usually realize light signal detection based on the photovoltaic (PV) effect in reverse bias mode. However, the external quantum efficiency (EQE) of devices in PV mode is low, less than 100%, and the photogenerated current is very small. In weak light signal detection, the photogenerated current of a single pixel in a CCD / CMOS array can be as low as pA level. Therefore, photodiodes are usually combined with preamplifier circuits in practical applications, which makes the imaging system structure more complicated and increases the cost.

[0004] The PM-OPD, which works based on the photomultiplier (PM) effect, has an EQE far greater than 100%, and has a stronger ability to detect weak light signals. At the same time, it does not require a preamplifier circuit, further meeting the requirements of imaging system integration and miniaturization. Today, the EQE of PM-OPD can often reach 10 5 This also means that the photocurrent of the device in PM mode is several orders of magnitude higher than that in PV mode. However, driving the device in PM mode usually requires a higher bias voltage, which will greatly increase the power consumption of the system. Especially when detecting strong light signals, the problems of anti-breakdown and heat dissipation caused by high power consumption cannot be ignored for OPD devices based on organic photosensitive layers.

[0005] In summary, both PV and PM devices are difficult to reconcile the conflict between the increasing demand for multi-scenario applications and high integration due to the limitations of their single working mode. Summary of the Invention

[0006] In order to solve the above-mentioned problems, the purpose of the present invention is to provide a dual-mode organic photodiode based on barrier layer interface regulation to solve the application limitations of organic photodiodes at this stage due to their single working mode.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A dual-mode organic photodiode based on barrier layer interface regulation includes a transparent substrate 1 at the bottom and a five-layer material structure above the transparent substrate 1. The five-layer material structure includes: a transparent bottom electrode layer 2, a first barrier layer 3, an organic photosensitive layer 4, a second barrier layer 5, and a top electrode layer 6;

[0009] The transparent bottom electrode layer 2 covers half of the upper surface of the transparent substrate 1, the upper surface of the transparent bottom electrode layer 2 and the upper surface of the transparent substrate 1 not covered by the transparent bottom electrode layer 2 are covered by a first barrier layer 3, and above the first barrier layer 3 are an organic photosensitive layer 4, a second barrier layer 5, and a top electrode layer 6 in sequence;

[0010] The first blocking layer 3 and / or the second blocking layer 5 have carrier traps for accumulating carriers at the interface with the organic photosensitive layer 4; under forward bias, the carrier traps at the interface between the first blocking layer 3 and / or the second blocking layer 5 and the organic photosensitive layer 4 trigger tunneling injection of carriers from the external circuit, so that the dual-mode organic photodiode based on blocking layer interface regulation operates in PM mode; under reverse bias, the first blocking layer 3 and the second blocking layer 5 on the upper and lower sides of the organic photosensitive layer 4 prevent the injection of carriers from the external circuit, so that the dual-mode organic photodiode based on blocking layer interface regulation operates in PV mode.

[0011] Preferably, the organic photosensitive layer comprises one or more organic semiconductor materials.

[0012] As a preferred embodiment, the material of the organic photosensitive layer is selected from: poly([2,6-4,8-bis-((2-ethylhexyl)-thiophen-5-yl)benzo[1,2-B(PBDB-T), poly[(2,6-(4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo[1,2-B:4,5-B']dithiophene])-ALT-(5,5-(1',3'-di-2-thiophene-5',7'-bis(2-ethylhexyl)benzo[1',2'-C:4 ',5'-C']dithiophene-4,8-dione)(PM6),poly(3-hexylthiophene-2,5-diyl)(P3HT),3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(5-hexylthienyl)-dithieno[2,3-d:2',3'-d']-s-indaceno [1,2-b:5,6-b']dithiophene(ITIC-Th),2,2'-((12,13-bis(2-ethylhexyl)-12,13-dihydro-3,9-heneicosylbisthieno[2",3":4',5']thieno[2',3':4,5]pyrrolo[3,2-e:2',3'-g][2,1,3]benzothiadiazole-2,10-diyl)bis(methylene( One or more of 5,6-difluoro-3-oxo-1H-indene-2,1(3H)-diylidene)))bis(malononitrile) (Y6), [6,6]-phenyl C61 butyric acid methyl ester, 1-[3-(methoxycarbonyl)propyl]-1-phenyl-[6.6]C613′H-cyclopropyl[1,9][5,6]fullerene-C60-IH-3′-butyric acid 3′-benzyl ester, 3-phenyl-3H-cyclopropyl[1,9][5,6]fullerene-C60-IH-3-butyric acid methyl ester (PC61BM).

[0013] As a preferred method, the preparation process of the barrier layer is: the barrier layer material is subjected to a vapor deposition, scraping, drop coating, spin coating or spraying process to form a first barrier layer on the upper surface of the bottom electrode layer to form a thin film, and the second barrier layer is covered on the upper surface of the organic photosensitive layer to form a thin film, and then the vapor deposition process is controlled, the material is doped, nano-imprinted, the template is grown, and thermal annealing or solvent annealing is performed to form chemical defects or morphological defects on the upper surface of the first barrier layer and / or the lower surface of the second barrier layer.

[0014] As a preferred embodiment, the method for controlling the chemical defects or morphological defects includes: controlling the evaporation rate of the barrier layer, or controlling the doping material, or annealing treatment.

[0015] As a preferred embodiment, the first blocking layer and the second blocking layer are electron blocking layers or hole blocking layers, the electron blocking layer material is selected from MoO3, PVK, poly-TPD, P3HT and PEDOT:PSS, and the hole blocking layer material is selected from ZnO, TiO2, PEIE, PEIE-Zn, LiF and SeO2.

[0016] As a preferred embodiment, the thickness of the organic photosensitive layer 4 is 100 nm to 2000 nm.

[0017] The present invention also provides a method for preparing a dual-mode organic photodiode based on barrier layer interface regulation, comprising the following steps:

[0018] Step 1: depositing a transparent bottom electrode on a transparent substrate by magnetron sputtering, thermal evaporation, or electron beam evaporation;

[0019] Step 2: Clean the transparent bottom electrode to remove impurities;

[0020] Step 3: applying a barrier layer material to the upper surface of the bottom electrode layer by evaporation, blade coating, drop coating, spin coating, or spraying to form a first barrier layer on the upper surface of the bottom electrode layer, and then performing evaporation process control, material doping, nanoimprinting, template growth, thermal annealing, or solvent annealing to form chemical defects or defect morphology on the upper surface of the first barrier layer and / or the lower surface of the second barrier layer;

[0021] Step 4: Spin coating, evaporation, blade coating, drop coating, or spray coating the organic photosensitive layer material to coat the upper surface of the first barrier layer;

[0022] Step 5: Applying a barrier layer material by evaporation, blade coating, drop coating, spin coating or spraying to form a thin film on the upper surface of the bottom electrode layer;

[0023] Step 6: depositing the top electrode by magnetron sputtering, thermal evaporation, or electron beam evaporation.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides a dual-mode organic photodiode based on barrier layer interface regulation, which has two working modes: photovoltaic (PV) and photomultiplier (PM). The mode is switched by controlling the direction of the external bias voltage, thereby meeting the multi-scenario application requirements of strong and weak light detection. Under reverse bias, the barrier layers on both sides of the organic photosensitive layer can prevent the injection of carriers from the external circuit, so that the dual-mode organic photodiode works in PV mode. At this time, the external quantum efficiency is limited and the photogenerated current is small, which is suitable for detection under strong light conditions and can avoid problems such as device breakdown and heat dissipation caused by high power consumption. Under forward bias, the carrier traps at the interface between the barrier layer and the organic photosensitive layer trigger the tunneling injection of carriers from the external circuit, so that the dual-mode organic photodiode works in PM mode. At this time, the external quantum efficiency is high and the photogenerated current is large, which is suitable for detection under weak light conditions and can avoid the use of preamplifier circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the device structure of the dual-mode organic photodiode based on barrier layer interface regulation in the present invention;

[0027] Figure 2 XPS characterization analysis of the upper surface of the first blocking layer in the dual-mode organic photodiode prepared in Example 1 and the control group;

[0028] Figure 3 This is a working principle diagram of the dual-mode organic photodiode prepared in Example 1;

[0029] Figure 4 EQE spectral response diagram of the dual-mode organic photodiode prepared in Example 1 and the control group.

[0030] Figure 5 EQE spectral response diagram of the dual-mode organic photodiode prepared in Example 2, Example 1 and the control group.

[0031] 1 is a transparent substrate, 2 is a transparent bottom electrode layer, 3 is a first barrier layer, 4 is an organic photosensitive layer, 5 is a second barrier layer, and 6 is a top electrode layer. DETAILED DESCRIPTION

[0032] The following describes the specific embodiments of the present invention through specific examples, which will help those skilled in the art to clearly understand the objectives, technical solutions, advantages, and effectiveness of the present invention. Obviously, the described embodiments are only a portion of the embodiments of the present invention, not all of them; all other embodiments derived by those skilled in the art based on the embodiments in this specification without making any inventive changes are also within the scope of protection of the present invention.

[0033] The embodiment provides a dual-mode organic photodiode based on barrier layer interface regulation, comprising a transparent substrate 1 at the bottom, and a five-layer material structure above the transparent substrate 1, wherein the five-layer material structure includes: a transparent bottom electrode layer 2, a first barrier layer 3, an organic photosensitive layer 4, a second barrier layer 5, and a top electrode layer 6;

[0034] The transparent bottom electrode layer 2 covers half of the upper surface of the transparent substrate 1, the upper surface of the transparent bottom electrode layer 2 and the upper surface of the transparent substrate 1 not covered by the transparent bottom electrode layer 2 are covered by a first barrier layer 3, and above the first barrier layer 3 are an organic photosensitive layer 4, a second barrier layer 5, and a top electrode layer 6 in sequence;

[0035] The first blocking layer 3 and / or the second blocking layer 5 have carrier traps for accumulating carriers at the interface with the organic photosensitive layer 4; under forward bias, the carrier traps at the interface between the first blocking layer 3 and / or the second blocking layer 5 and the organic photosensitive layer 4 trigger tunneling injection of carriers from the external circuit, so that the dual-mode organic photodiode based on blocking layer interface regulation operates in PM mode; under reverse bias, the first blocking layer 3 and the second blocking layer 5 on the upper and lower sides of the organic photosensitive layer 4 prevent the injection of carriers from the external circuit, so that the dual-mode organic photodiode based on blocking layer interface regulation operates in PV mode.

[0036] In some embodiments, the organic photosensitive layer comprises one or more organic semiconductor materials.

[0037] In some embodiments, the material of the organic photosensitive layer is selected from the group consisting of: poly([2,6-4,8-bis-((2-ethylhexyl)-thiophen-5-yl)benzo[1,2-B(PBDB-T), poly[(2,6-(4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo[1,2-B:4,5-B']dithiophene])-ALT-(5,5-(1',3'-di-2-thiophene-5',7'-bis(2-ethylhexyl)benzo[1',2'-C:4',5'-C']dithiophene-4,8-dione))(PM6), poly(3-hexylthiophene-2,5-diyl)(P3HT), 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanon e))-5,5,11,11-tetrakis(5-hexylthienyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene(ITIC-Th),2,2'-((12,13-bis(2-ethylhexyl)-12,13-dihydro-3,9-hexadecanylbisthieno[2",3":4',5']thien o[2',3':4,5]pyrrolo[3,2-e:2',3'-g][2,1,3]benzothiadiazole-2,10-diyl)bis(methylene(5,6-difluoro-3-oxo-1H-indene-2,1(3H)-diylidene)))bis(malononitrile)(Y6),[6,6]-phenylC61butyric acid methyl ester 1-[3-(methoxycarbonyl)propyl]-1-phenyl-[6.6]C613′H-cyclopropyl[1,9][5,6]fullerene-C60-IH-3′-butyric acid 3′-benzyl ester 3-phenyl-3H-cyclopropyl[1,9][5,6]fullerene-C60-IH-3-butyric acid methyl ester (PC61BM) or one or more thereof.

[0038] In some embodiments, the preparation process of the barrier layer is as follows: the barrier layer material is subjected to evaporation, scraping, dripping, spin coating or spraying processes to form a first barrier layer on the upper surface of the bottom electrode layer, and a second barrier layer is formed on the upper surface of the organic photosensitive layer. The evaporation process is then controlled, the material is doped, nano-imprinted, the template is grown, thermally annealed or solvent annealed to form chemical defects or morphological defects on the upper surface of the first barrier layer and / or the lower surface of the second barrier layer.

[0039] In some embodiments, the method for controlling the chemical defects or morphological defects includes: controlling the evaporation rate of the barrier layer, or controlling the doping material, or annealing treatment.

[0040] In some embodiments, the first blocking layer and the second blocking layer are electron blocking layers or hole blocking layers, the electron blocking layer material is selected from MoO3, PVK, poly-TPD, P3HT and PEDOT:PSS, and the hole blocking layer material is selected from ZnO, TiO2, PEIE, PEIE-Zn, LiF and SeO2.

[0041] In some embodiments, the thickness of the organic photosensitive layer 4 is 100 nm to 2000 nm.

[0042] In some embodiments, the method for preparing a dual-mode organic photodiode based on barrier layer interface regulation comprises the following steps:

[0043] Step 1: depositing a transparent bottom electrode on a transparent substrate by magnetron sputtering, thermal evaporation, or electron beam evaporation;

[0044] Step 2: Clean the transparent bottom electrode to remove impurities;

[0045] Step 3: applying a barrier layer material to the upper surface of the bottom electrode layer by evaporation, blade coating, drop coating, spin coating, or spraying to form a first barrier layer on the upper surface of the bottom electrode layer, and then performing evaporation process control, material doping, nanoimprinting, template growth, thermal annealing, or solvent annealing to form chemical defects or defect morphology on the upper surface of the first barrier layer and / or the lower surface of the second barrier layer;

[0046] Step 4: Spin coating, evaporation, blade coating, drop coating, or spray coating the organic photosensitive layer material to coat the upper surface of the first barrier layer;

[0047] Step 5: Applying a barrier layer material by evaporation, blade coating, drop coating, spin coating or spraying to form a thin film on the upper surface of the bottom electrode layer;

[0048] Step 6: depositing the top electrode by magnetron sputtering, thermal evaporation, or electron beam evaporation.

[0049] Example 1

[0050] The dual-mode organic photodiode provided in this embodiment based on the regulation of the barrier layer interface has a structure as follows: Figure 1 As shown, it includes a transparent substrate 1 at the bottom and a five-layer material structure above the transparent substrate 1. The five-layer material structure includes: a transparent bottom electrode layer 2, a first barrier layer 3, an organic photosensitive layer 4, a second barrier layer 5, and a top electrode layer 6;

[0051] The transparent bottom electrode layer 2 covers half of the upper surface of the transparent substrate 1, the upper surface of the transparent bottom electrode layer 2 and the upper surface of the transparent substrate 1 not covered by the transparent bottom electrode layer 2 are covered by a first barrier layer 3, and above the first barrier layer 3 are an organic photosensitive layer 4, a second barrier layer 5, and a top electrode layer 6 in sequence;

[0052] The first blocking layer 3 and / or the second blocking layer 5 have carrier traps for accumulating carriers at the interface with the organic photosensitive layer 4; under forward bias, the carrier traps at the interface between the first blocking layer 3 and / or the second blocking layer 5 and the organic photosensitive layer 4 trigger tunneling injection of carriers from the external circuit, so that the dual-mode organic photodiode based on blocking layer interface regulation operates in PM mode; under reverse bias, the first blocking layer 3 and the second blocking layer 5 on the upper and lower sides of the organic photosensitive layer 4 prevent the injection of carriers from the external circuit, so that the dual-mode organic photodiode based on blocking layer interface regulation operates in PV mode.

[0053] The dual-mode organic photodiode based on barrier layer interface regulation adopts an inversion structure, and the specific preparation method includes the following steps:

[0054] Step 1: depositing an indium tin oxide (ITO) thin film with a thickness of 150 nm on a transparent glass substrate by magnetron sputtering;

[0055] Step 2: The substrate with the ITO film deposited was immersed in detergent, deionized water, acetone, and isopropyl alcohol, respectively, and ultrasonically cleaned for 15 minutes, then blown dry with a nitrogen gun, and the electrode surface was cleaned with ultraviolet ozone for 20 minutes to obtain a transparent conductive electrode;

[0056] Step 3: In this embodiment, the first barrier layer is a hole barrier layer, which is a ZnO film; 200 mesh ZnO powder is used and the pressure is less than 1x10 -4 Thermal evaporation was performed under vacuum conditions of 1000 Pa, with a substrate stage rotation speed of 11 RPM and an evaporation rate controlled at 0.03 nm / s, resulting in a total film thickness of 20 nm. Under the high-temperature conditions of thermal evaporation, ZnO undergoes elemental mismatch, and the resulting ZnO film is doped with a small amount of elemental Zn. This introduces chemical defects that act as carrier traps at the interface between the barrier layer and the organic photosensitive layer. The control ZnO barrier layer film exhibits no carrier traps.

[0057] Step 4: Organic semiconductor materials PBDB-T and ITIC-Th were used as organic photosensitive layer materials. They were dissolved in the organic solvent chlorobenzene at a mass ratio of 1:1 to a total concentration of 30 mg / ml. The solution was stirred on a heated stirring platform at 50°C for at least 12 hours. Under a nitrogen atmosphere, an organic photosensitive layer was prepared on the surface of the ZnO hole-blocking layer using a spin coating process at a speed of 2000 rpm, an acceleration of 10,000 rpm / s, and a time of 40 seconds. The organic photosensitive layer was then annealed at 110°C for 10 minutes under a nitrogen atmosphere. The resulting organic photosensitive layer had a thickness of approximately 200 nm.

[0058] Step 5: In this embodiment, the second blocking layer is used as an electron blocking layer. The material is MoO3 with a thickness of 10 nm. It is prepared on the surface of the organic photosensitive layer by vacuum thermal evaporation. The evaporation pressure is less than 1x10 -4 Pa.

[0059] Step 6: In this embodiment, the top electrode layer is prepared by vacuum thermal evaporation on the surface of the electron blocking layer obtained in step 5. The electrode material is metallic silver (Ag), and the evaporation pressure is less than 1x10 -4 Pa, the film thickness is 100 nm.

[0060] A control group was prepared according to the above steps. The device structure in this control group was identical to that in Example 1, except that the first barrier layer in this control group was prepared using a spin-coating process: a ZnO precursor solution was spin-coated onto the transparent bottom electrode at a speed of 4000 rpm, an acceleration of 10,000 rpm / s, and a duration of 40 seconds. The device was then thermally annealed in an atmospheric atmosphere at 200°C for 30 minutes. Consequently, no carrier traps were formed at the interface between the barrier layer and the organic photosensitive layer.

[0061] Figure 2 This is an analysis chart of the XPS characterization results of the barrier layer of the dual-mode organic photodiode based on barrier layer interface regulation and its control group device. Figure 2 As shown, the Zn Auger spectrum of the barrier layer prepared by vacuum thermal evaporation in Example 1 contains both ZnO and Zn peaks, while the Zn Auger spectrum of the barrier layer prepared by spin coating in the control group contains only a single ZnO peak. This indicates that the free Zn in the ZnO film prepared by vacuum thermal evaporation acts as a chemical defect in the multiplication process, while the ZnO film prepared by spin coating in the control group does not have this defect.

[0062] The mechanism of the present invention is as follows: by regulating the interface between the barrier layer and the organic photosensitive layer, a carrier trap is formed on the interface, so that the photogenerated carriers are bound by the carrier trap at the interface between the barrier layer and the organic photosensitive layer, thereby inducing tunneling injection of carriers from the external circuit. Taking a device with a carrier trap at the interface between the first barrier layer and the organic photosensitive layer as an example, Figure 3As shown, the dual-mode organic photodiode based on barrier layer interface regulation in Example 1 has a low dark current under reverse bias due to the energy level blocking of the MoO3 barrier layer and the ZnO barrier layer. Under illumination, the photogenerated electrons and holes in the organic photosensitive layer are collected by the ITO / Ag electrodes to generate photogenerated current, and the device operates in PV mode. Under forward bias, due to the obstruction of carrier transport at the interface between the barrier layer and the organic photosensitive layer, the dark current is reduced compared to the device in the control group without carrier traps at the interface between the barrier layer and the organic photosensitive layer. Under illumination, the carrier traps at the interface between the barrier layer and the organic photosensitive layer and the blocking of the ZnO layer cause photogenerated holes to be trapped at the ZnO / organic photosensitive layer interface. The photogenerated electrons are blocked by the MoO3 layer and then accumulate at the organic photosensitive layer / MoO3 interface. As the photogenerated holes are trapped at the interface between the barrier layer and the organic photosensitive layer, they continue to accumulate, enhancing the curvature of the interface energy band, ultimately triggering electron tunneling injection, thereby producing the PM effect. Therefore, the dual-mode organic photodiode based on blocking layer interface regulation in Example 1 can operate in PV and PM modes under reverse bias and forward bias, respectively.

[0063] The technical effects of the present invention are verified by specific test data below:

[0064] The dual-mode organic photodiode based on barrier layer interface regulation of Example 1 and its control group device were tested in the test band of 300-800nm. Figure 4 As can be seen, the dual-mode organic photodiode device of Example 1 operates in PV mode at a bias of -0.5V, where the EQE is less than 100%. However, at a bias of +2V, the device achieves an EQE exceeding 100%, operating in PM mode. The control group device, on the other hand, can only operate in PV mode under reverse bias.

[0065] Example 2

[0066] The difference between Example 2 and Example 1 is that carrier traps are also added at the interface between the organic photosensitive layer and the second barrier layer, and the process for forming the carrier traps is different from that in Example 1, and thermal annealing is used to form interface defects. In Example 2, carrier traps exist at the interface between the first barrier layer and the organic photosensitive layer, and at the interface between the organic photosensitive layer and the second barrier layer; in the control group, there are only carrier traps at the interface between the organic photosensitive layer and the second barrier layer formed by thermal annealing. Specific experimental data are as follows. Figure 5 As shown, the PM mode performance is better than that of devices containing only one type of carrier trap.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dual-mode organic photodiode based on barrier layer interface regulation, characterized by: It comprises a transparent substrate (1) at the bottom and a five-layer material structure above the transparent substrate (1), wherein the five-layer material structure comprises: a transparent bottom electrode layer (2), a first barrier layer (3), an organic photosensitive layer (4), a second barrier layer (5), and a top electrode layer (6); The transparent bottom electrode layer (2) covers half of the upper surface of the transparent substrate (1); the upper surface of the transparent bottom electrode layer (2) and the upper surface of the transparent substrate (1) not covered by the transparent bottom electrode layer (2) are covered by a first barrier layer (3); and above the first barrier layer (3) are an organic photosensitive layer (4), a second barrier layer (5), and a top electrode layer (6); The first blocking layer (3) and / or the second blocking layer (5) have carrier traps for accumulating carriers at the interface with the organic photosensitive layer (4); under a forward bias, the carrier traps at the interface with the first blocking layer (3) and / or the second blocking layer (5) and the organic photosensitive layer (4) trigger tunneling injection of carriers from an external circuit, so that the dual-mode organic photodiode based on blocking layer interface regulation operates in a photomultiplier mode; under a reverse bias, the first blocking layer (3) and the second blocking layer (5) on the upper and lower sides of the organic photosensitive layer (4) prevent injection of carriers from an external circuit, so that the dual-mode organic photodiode based on blocking layer interface regulation operates in a photovoltaic mode.

2. The dual-mode organic photodiode based on barrier layer interface regulation according to claim 1, characterized in that: The organic photosensitive layer comprises one or more organic semiconductor materials.

3. The dual-mode organic photodiode based on barrier layer interface regulation according to claim 1, characterized in that: The material of the organic photosensitive layer is selected from: Poly[(2,6-(4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene))-alt-(5,5-(1',3'-di-2-thiophene-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione))], Poly[(2,6-(4,8-bis(5-(2-ethylhexyl-3-fluoro)thiophen-2-yl)-benzo[1,2-b:4,5-b']dithiophene])-alt-(5,5-(1',3'-di-2-thiophene-5',7'-bis(2-ethylhexyl)benzo[1',2'-c:4',5'-c']dithiophene-4,8-dione), Poly(3-hexylthiophene-2,5-diyl), 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(5-hexylthienyl)-dithieno[2,3-d:2',3'-d']-s-indaceno[1,2-b:5,6-b']dithiophene, 2,2'-((12,13-bis(2-ethylhexyl)-12,13-dihydro-3,9-heneicosylbisthieno[2'',3'':4',5']thieno[2',3':4,5]pyrrolo[3,2-e:2',3'-g][2,1,3]benzothiadiazole-2,10-diyl)bis(methylene(5,6-difluoro-3-oxo-1H-indene-2,1(3H)-diylidene)))bis(malononitrile), [6,6]-phenyl C61 butyric acid methyl ester 1-[3-(methoxycarbonyl)propyl]-1-phenyl-[6.6]C61 3′H-cyclopropyl[1,9][5,6]fullerene-C60-IH-3′-butyric acid 3′-benzyl ester 3-phenyl-3H-cyclopropyl[1,9][5,6]fullerene-C60-IH-3-butyric acid methyl ester One or more thereof.

4. The dual-mode organic photodiode based on barrier layer interface regulation according to claim 1, characterized in that: The preparation process of the barrier layer is as follows: the barrier layer material is subjected to evaporation, scraping, drop coating, spin coating or spraying technology to form a first barrier layer on the upper surface of the bottom electrode layer, and a second barrier layer is formed on the upper surface of the organic photosensitive layer. The evaporation process is then controlled, the material is doped, nano-imprinted, the template is grown, and thermal annealing or solvent annealing is performed to form chemical defects or morphological defects on the upper surface of the first barrier layer and / or the lower surface of the second barrier layer.

5. The dual-mode organic photodiode based on barrier layer interface regulation according to claim 4, characterized in that: The method for controlling the chemical defects or morphological defects includes: controlling the evaporation rate of the barrier layer, controlling the doping material, or performing annealing treatment.

6. The dual-mode organic photodiode based on barrier layer interface regulation according to claim 1, characterized in that: The first blocking layer and the second blocking layer are electron blocking layers or hole blocking layers, the electron blocking layer material is selected from MoO3, PVK, poly-TPD, P3HT and PEDOT:PSS, and the hole blocking layer material is selected from ZnO, TiO2, PEIE, PEIE-Zn, LiF and SeO2.

7. The dual-mode organic photodiode based on barrier layer interface regulation according to claim 1, characterized in that: The thickness of the organic photosensitive layer (4) is 100 nm to 2000 nm.

8. The method for preparing a dual-mode organic photodiode based on barrier layer interface regulation according to any one of claims 1 to 7, characterized in that The steps include: Step 1: depositing a transparent bottom electrode on a transparent substrate by magnetron sputtering, thermal evaporation, or electron beam evaporation; Step 2: Clean the transparent bottom electrode to remove impurities; Step 3: applying a barrier layer material to the upper surface of the bottom electrode layer by evaporation, blade coating, drop coating, spin coating, or spraying to form a first barrier layer on the upper surface of the bottom electrode layer, and then performing evaporation process control, material doping, nanoimprinting, template growth, thermal annealing, or solvent annealing to form chemical defects or defect morphology on the upper surface of the first barrier layer and / or the lower surface of the second barrier layer; Step 4: Spin coating, evaporation, blade coating, drop coating, or spray coating the organic photosensitive layer material to coat the upper surface of the first barrier layer; Step 5: applying a barrier layer material by evaporation, blade coating, drop coating, spin coating or spraying to form a second barrier layer on the upper surface of the organic photosensitive layer; Step 6: depositing the top electrode by magnetron sputtering, thermal evaporation, or electron beam evaporation.

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